Inhibiting gel formation in fuel oils



U t Sta s ate INHIBITING GEL FORMATION 1N FUEL OILS Philip L. Bartlett, Wilmington, Del., assignor to E. L dn Pont de Nemours and Company, Wilmington, Del., a corporation of Delaware No Drawing. Filed Aug. 27,1956, Ser. No. 606,186

20 Claims. (Cl. 44 66) This invention relates to inhibiting the formation of copper mercaptide gels in hydrocarbon distillate fuel oils and to liquefying preformed copper mercaptide gels.

It is known that a gel frequently is formed in hydrocarbon distillate fuel oils under storage andservice conditions, such as in domestic oil burner installations, diesel service and the like, and forms gelatinous deposits in the equipment which plug lines, orifices, filter screens, and the like. The gel is formed in the presence of copper or brass equipment, such as brass filters, floats and needle valves, and copper tubing and contains copper mercaptides which act as the gelling agents. This gel' is con- I mately 0.1 to" 1.0%), the copper being in the cuprous' form, and .of major proportions of hydrocarbon components (at least 95% and sometimes over 99%); also small quantities of oxygenated material and water are 2,980,518 n ed Arr- .18, 19

sition of such gels on surfaces'in contact therewith. All? other object is to provide concentrated solutions of such inhibitors for ready and economical transportation and use thereof, including particularly for use in liquefying preformed copper mercaptide gel. A further object is to provide a process for liquefying' copper mercaptide gel and, particularly, for removing deposits of such gel from equipment. Other objects are to provide new compo sitions of matter and to advance the art. Still o her objects will appear hereinafter. 3

The above and other objects may beaceomplished in accord with this invention which comprises (1) a hydrocarbon distillate fuel oil which contains at least one mercaptan which normally tends to form a copper mercaptide gel and to which fuel oil th'ere has been added a small proportion, sufficient to inhibit such gel formation, of at least one polyamino compound of the group consisting of alkylene primary dia mines of2 to 10 carbon atoms in which the primary amino groupsare separated by 2 to 6 carbon atoms, dialkylenetriamines of 4 to '10 carbon atoms in which the amino groups 'are'separated by 2 to 4 carbon atoms and two of the amino groups are primary amino groups, and mono-acid salts of said diamines and said triamines in which the acids are selected from the group consisting ofmonocarboxylic fatty acids of 8 to about 22 carbon atoms,monohydric mononuclear phenols, and monocarboxylic petroleum naphth enic acids of about 8 to about 29 carbon atoms; (2) the process .of liquefying a gel, formed by the action of a copper mercaptide on a normally liquid hydrocarbomby adding'to said gel at least '1% by weight'of at least oneof said polyamino compounds, as such or as a concentrated sohrtion in a normally liquid hydrocarbon; and (3) concertoften present. The usual fuel oil sludge inhibitors are ineffective in preventing formation of such gel andin breaking-up existing gel.

Sulfur-compounds generally occur as impurities in all petroleum hydrocarbon products, the type and quantity of the sulfur compounds being'determined by the source 1 r and previous processing history of the petroleum product. Mercaptans, in particular, have hithertobeen objection- "able to the industry for various reasons (odor, corrosiveness, .etc.) and many processes have been devised. for

ing them" more or less completely from petroleum products. "How ever, likev all refining processes, these are costly,and some are ratherinefiicient. in destroying or removing mercaptans. .As a result, many hydrocarbon distillate fuels are often marketed unrefined or only partially refined, with mercaptans. still present in various amounts, depending ontheirflultimate -use,1,part i'cularly* 'fuel oils. designatedas'burner, heating, orfurnace oil. The mercaptansjulfur"content. of such fuel oils mayrange from as low *as:0.00 1 weight percentfto :as high as about Where careful; refining of1all: gradesv of hydrocarbon equipment.

' Iris an object of'this invention to v provide hydro carbon distillate fuel oils containingcompounds which inhibit the formation .otcopper mercapti'de gel; therein and the: depoconverting them into innocuous materials or for eliminati where m is is equal to 0 or 1 aIk-ylene is a divalent sattrated solutions of at least one ofsaid polyamino conr pounds in a normally liquid hydrocarbon.

It has been found that the polyamino compounds of this invention, when added 'in a small. proportion 'to a hydrocarbon distillate fuel oil that contains at least one mercaptan which normally tends to form' a copper merecaptide gel when the fuel oil is brough into contact with copper or brass, are very effective *to'inhibit such gel formation and the depositionof 'such' gelmon surfaces with which the fuel oil may bebrought into'co'n'tact. It has been found further that when smallproportion's of said polyamino compounds, as such or as'concentrated solutions in normally liquid hydrocarbons, are'addedfto copper mercaptide gels, the gels are broken up (liquefied) and can be readily removed from equipmentby washing with'a normally liquidhydrocarbon, whereby such equipment can be unplugged and cleaned of'such'gelswithout stripping down or dismantling the equipment.

. The alkylene primary diamines and" the dialkylene .triamines together may be represented by the formulaz .urated aliphatic hydrocarbon radical C H and the nitrogen atoms are bonded to different carbon, atoms. In the alkylene primary diamines, m is equal to 0, n representsran integer of V2 to 10, preferably 2 6,"an'd the- .twoNHg groups are separated by 2 m6 carbon-atoms, preferably 2m. 4 carbon atoms. Inthedialkylene tri amines,.'m is equalto 1, n in each alkylene grouprepresents an integer-of 2 to'8, preferably 2- to'-4, and the.

5 groups may :be straight or branched chain. Thef'amino 'groupsmay lac attached to primary, secondary ortertiar-y carbon atoms; the term;.primary.gin;falkylenepringary qdiarnine referring, toithe primary amino groups (*NHQ.

s In the dialkylene triamines, the alkylene units may be the same or difierent. Homologous alkylene primary diamines and dialkylene triamines containing more than 'carbon atoms, while operable, are generallyless desirable for reasons of cost and economy.

j Representative alkylene diamines are: ethylene diamine; 1,2-propylene diamine; 1,3-propylene diamine; l,3-diamino-2-methylpropane, 1,3-diamino-2,2-dimethylpropane; the 1,2-, 1,3-, 1,4-,and 2,3-butylene diamines and carbon-alkylated derivatives such as 2,3-diamino-2- methylbutane and 1,4-diamino-2-ethylbutane; pentylene diamines typified by 1,2-, 2,4-, and 1,5-diaminopentane, including carbon alkylated compounds such as 1,4-diamino-4-methylpentane and 2,4-diamino-2,4-dimethylpentane; hexylene diamines represented by 1,6-hexylene diamine (hexamethylene diamine) and 2,4-hexylene diamine, and including higher homologs such as 2,5-diamino-2,S-dimethylhexane.

Typical dialkylene'triamines of this invention are: 1,2- diethylene triamine; 1,2- and 1,3-dipropylene triamine; and the corresponding dibutylene triamines in which each pair of nitrogen atomsin the chainis separated by at least 2 carbon atoms.

Fuel oil soluble mono-acid salts of the hereinbefore defined alkylene primary diamines and dialkylene triamines. are also effective for the purposes of this invention. Such mono-acid salts contain one mole of the acid. for each mole of the polyamine and are prepared by methods well known and conventional in the art, such as by mixing the polyamine with the organic acid in equimolecular proportions at atmospheric temperature, the reaction being substantially instantaneous. Suitable organic acids are monocarboxylic fatty acids of 8 to about 22 carbon atoms, monohydric mononuclear phe- 11015, and monocarboxylic petroleum naphthenic acids of about 8 to about 29 carbon atoms. These mono-acid salts offer the advantageof increased .fuel oil solubility over the corresponding polyamine, especially with the "lower members of the series, e.g., ethylene diamine and diethylene triamine. They are particularly desirable for the preparation of concentrated solutions in normally liquid hydrocarbons.

Representative monocarboxylic fatty acids of this in .vention are ole'ic acid, caprylic acid, pelargonic (nonanoic) acid, undecylic acid, lauric acid, stearic acid, linoleic acid, linolinic acid, behenic'acid, and the like. Oleic 'acid is preferred.

Representative monohydric mononuclear phenols 'are phenol, thecresols, the ethyl phenols, the xylenols, and the like. Particularly desirable are the commercially available mixturese known as cresylic acids (a mixture of o-, mand p-cresols) and xylenols. Such mixtures result in mixtures of the mono-acid polyamine salts of -cyclopentane, its homologs and bicyclic derivatives. The

carboxyl group is usually attached to a' parafi'inic side refined commercial naphthenic acids, and hence are mixtures of the mon-acid salts of the several napthenic acids.

Representative mono-acid salts of this invention which have been found to be particularly satisfactory for the purposes of this invention are:

Ethylene diamine monooleate 1,2-propylene diamine monooleate 2,3-butylene diamine monooleate Diethylene triamine monooleate Ethylene diamine mononaphthenate Diethylene triamine mononaphthenate Ethylene diamine monocresylate Diethylene triamine monocresylate The hydrocarbon distillate fuel oils, to which the polyamino compounds of this invention are to be added, are the hydrocarbon distillates which areheavier than gasoline and which are known to the art as furnace oil, burner oil, heating oil, range oil, diesel fuel, jet fuel, and fuel oil. In general, these. oils have a boiling range of frornabout 300 F. to about 750 F. Also, the hydrocarbon distillate fuel oils contain active mercaptans. Active mercaptans are those which, when fuel oil containing them is brought into contact with copper, copper compounds. or brass, will react therewith to form copper mercaptides that form copper mercaptide gels. The most active mercaptans are. the aliphatic mercaptans, the activity thereof decreasing from the primary to the secondary to the tertiary mercaptans. Usually, aromatic mercaptans alone do notform solid copper mercaptide gels but, in the presence of an aliphatic primary mercaptan, they and the aliphatic secondary and tertiary mercaptans appear to contribute to the formation of such gels. I i i The occurrence of mercaptans of all types in distillate hydrocarbon fuel oils is well known. Commercial hydrocarbon distillate fuel oils offered today for "heating use, contain, when fresh from as low as 0.001% to as high as 0.03% by weight of mercaptan sulfur. This mercaptan sulfur content varies, depending on the source of the fuel oil, its processing history, and its age- For example, the mercaptan; sulfur content of catalytic cracked fuel oil tends to diminish on aging, which may be attributed to the reaction of mercaptans with olefin groups under :conditions of storage. Thus, while the tendency of some fuel oils to form sludge, increases on aging, the tendencyto .form copper mercaptide gel may actually decrease during this same period. Even quite minute quantities of active mercaptan sulfur in a fuel oil tends to result in objectionable.troublesome fouling of equipment, that is, small quantities of active mercaptan sulfur cause the deposition of rather large volumes of fuel oil as an insoluble gelatinous precipitate.

Generally, the quantity of polyamine compound of this invention which will be added'to a hydrocarbon distillate fuel oil is from 0.1 to. about 5 parts byweight for each part of active'rnercaptan sulfur present in the fuel oil, preferably from about 0.5 to about 3 parts by weight. For most hydrocarbon distillate fuel oils, this will be from 0.0001% toabout 0.15% by weight based on the fuel oil, preferably from about 0.0005% to chain of the ring, but may be directly attached to a ring carbon atom'. The commercially available'products, ob-

tainedfrom various petroleum sources aire mixtures or "naphthenic acids of frorn*7'.or 8 to about '29 carbon atoms, usually not more than 20 carbon'fatoms and av eraging about 12 to 14 carbon atoms, sometimes also containing minor proportions of fatty acids and carboxylic acids derived from cyclohexane and its homologs. Refined comniercialnaphthenic acids generally have an apparent molecularweight of 'abputi200-250which cerrespondstoanaverage of 1 2 to 14 carbon atoms in the molecule. "The naphthenic acid .morio ,salts" or mono- 'naphthenates of the examples were prepared from such about 0.1%. Larger a mounts of polyamine compound may be used, but generally. will be wasteful unless the fuel oil contains unusually large amounts of active mercaptan sulfur or it is to be used in equipment whichuis already fouled with copper mercapticle gel.

'Afpolyamino compound of this invention or a mixture of any two or more thereofmay be added as such to the hydrocarbon distillate fuel oil at atmospheric temperature or, if desired, at moderately elevatedterhperature and stirring until solution is complete. Preferablly the polyamin'o compound or mixture of compounds will be'add'ed in the form of a concentrated solution in a normally liquid hydrocarbon, such as benzene,

toluene, xylene, gasoline, kerosene, fuel oils, and tlre Iike. Generally, the polyamino compounds will be in a Concentration of from about to about 70% by weight, preferably from about 30% to about 50% by weight. These concentrated solutions represent the commercial form in which the polyamino compound will be shipped to the refiner for addition to the fuel oil to be treated. Such solutions are more convenient to transport, to handle (e.g. pour) and to measure. The maximum concentration obtainable will depend upon the solubility of the polyamino compound in the liquid hydrocarbon and, for this purpose, it will be most desirable to employ those compounds of high solubility, preferably the mono-acid salts of the polyamines. Also, since the viscosity of the solution increases with increase in concentration of polyamino compound therein, the concentration generally will be limited by the maximum viscosity which can be efiiciently poured and measured, usually a concentration of not more than about 50% by weight being optimum for this purpose. f

For the purpose of breaking up and removing gel which has been formed in a system, an excess of polyamino compound may be incorporated in the fuel oil supply itself. However, this procedure will be fairly slow in removing the gel due to the low concentrations of the polyamino compound once it has finally diffused through the oil into the gel. On the other hand, rapid and effective breaking up of the gel has beenobtained by adding the polyamino compound, as such, directly to the gel. However, it is preferred to employ concentrated solutions of the polyamino compound or of a mixture thereof in a normally liquid hydrocarbon. The concentrated solutions, described in the next precedingparagraph, are suitable for this purpose, preferably those in which the polyamino compounds are in a concentration of from about 15% to about 30% by weight, particularly in kerosene. As little as 1 part of polyamino compound is elfective to liquefy up to 100 parts .by weight of gel. Larger amounts may be used, but large excesses are wasteful.

In breaking up and removing gel from equipment which has become coated or fouled with the gel, it is' desirable to bring the polyamino compounds rapidly into compound. If'a domestic oil burner becomes plugged with gel: during operatiouwith an untreated fuel oil, thepolyamino compound can be addedto the system at any 7 point'which leads to the affected parts. For? example, the

feed lines can be disconnected from the fuel oil storage '6 it is was used or'handled in a concentrated solution-,the concentration thereof, and whether it isto'be; usedto break up preformed gel. While any of the polyamino compounds of this invention may be used very effectively to inhibit copper mercaptide gel formation in fuel oil,

it will be preferred to employ any one or more of ethylene diamine, diethylene trimine, the propylene diamines, the dipropylene triamines, and the monoleates and mononaphthenates of those polyamines. In breaking up or liquefying preformed copper mercaptide gel, the polyamino compounds vary in effectiveness, hexamethyle'ne diamine being much less effective for this purpose than those diamines in which the amino groups'are separated by fewer carbon atoms, the effectiveness increasing with decrease in the numberof carbon atoms-separating the amino groups. Thus, in breaking up preformed gel, it is preferred to employ alkylene diamines in which the two amino groups are separated by 2 to 4 carbon atoms,

' especially 2 to 3 carbon atoms, and dialkylene triamine's in which each amino group is separated from the nearest other amino group by 2 to 3 carbon atoms.

Higher polyalkylene polyamines, i.e., the trialkylene tetramines and the tetraalkylene pentamines, have little orno effect to inhibit the formation of copper merca'p- I tide gel in fuel oil or to break up preformed gel.- For example, it has been found that tetraethylene pentamine neither inhibits nor breaks up copper mercaptide gel. Similarly, when the polyamines of this invention are alkylated to convert one orboth of the primary amino groups to a secondary or a tertiary amino group, such as the N-alkyl-, N-N-dialkyl-, or N,N'-dialkyl-substituted compounds, their effectiveness for the purposes of this invention is greatly decreased or destroyed.v V

' The polyamino compounds of this invention may be employed in hydrocarbon distillate, fuel oils along .with other additives which are conventionally employed to impart other desirable characteristics to the, base oil,

such as resistance to discoloration and the formationof tank, and the-fuelremaining therein drained or blown: out I i and replaced by a concentrated solution of the polyamino compound.. The system isthen tested for normal flow. The cleaning operation c an be repeated as may be necessary, using fresh solution:or'recirculating the old solution through the contaminated'parts, e.g., nozzle, filter screen, or feed line. Finally, theequipmentshould be rinsed'with -a normally liquid hydrocarbon; which does not contain polyamino compound, as before. ..Since concentrated solutions of the polyamino compounds are I flr ather corrosive to coppe'nin the presenceofroxygen 1 'and/orgmoisturqit is desirableto washsuchsblutions" fromcopper-surfaces assoon as possibleafter the' poly amino compounds have broken up the gels, i.e., to. rinse them as set forth above.

; ;Theparticularpolyarnino compound or mixture there-5 {employed will-depend upon the manner aridlform in played in-Exa'mple 'l instead of 0.;1we'ight' percent of the above polyamines of this invention. Solid gel formed: I

sludge and to improve the combustion of the oil'.

In orderto more clearly illustratezthis invention, suitable modes of carrying it into effect, and the advantageousresults to be obtained thereby, the following examples are given in which the polyamino compounds employed are technical grade products and the, salts were prepared by mixing one .mole of. theorg'anic acid, carboxylic acid or phenol, with one mole of the polyamino at .room temperature: v

. Example I J A 'five" portion of catalytically cracked pf ilel oil containing a) a total of 0.4.weight percent mercaptan sulfer present as added dodecyl' mercaptan and" (b) 0.1

copper present as added copper naphthenate. No insoluble gel formed; the mixture remaining mobile and free-of gelindefinitely (for at least several weeks).

Ina control experiment, under identical conditions "except that no ethylene diarnine' was present, imme diate gelation of the fuel: took place.-

When ethylene diamine was replaced in the above example by an'equal weight of any of the following polyamines, complete inhibition of solid Igel' formation was observed-:- 1 2-propylene diamine, 1,3-propy-lene diamine, l,? -,butylenej ;diamine hexamethylene. diamine,

diethylene'triamine, di-(l,3-propylene), triarniriek' The Y i mixture, in each case, remained-free of gel. indefinitely.

In contrast, solid gel" was .formedimmediately-when 0.2 weightpercent of-tetraethylene -pentamine waseminlO minutes when as much fa gawei'lghtripercentvof ''3-diethylaminopropylaniine" was similarly ftes'te'd as an 'lwhi ch'it isto be usediandthe results desired,.i.'e., whether" inhibitor;. likewise; witha2' weightvpercenfi of: 3-i'sopro-Q pylaminopropylamine present the mixture solidified to gel in 3 minutes. r Example2 h A solid copper mercaptide gel was prepared by mixing (a) an equal volume of catalytically cracked fuel oil containing 0.4 weight percent mercaptan sulfur, present :as added dodecyl mercaptan, with (b) anequal volume of fuel oil containing 0.4% copper, present as added copper naphthenate. To samples of this 'solid gel (9 parts each) was added from 0.15 to 0.25 part of diethylene triamine and themixture was shaken. .In a few moments, the gel broke up (completely liquefied), in each case, the original straw color changing to the bluishgreen color of the copper-polyamine complex.

Example. 3

Solid copper mercaptide gel (containing 0.2 weight percent copper) was prepared by mixing equal volumes of catalytically cracked fuel oil containing, respectively, 0.4 weight percent mercaptan sulfur ,as a 1:1 mixture of dodecyl. and xylylmercaptans and 0.4% copper as the naphetenate. One part samples of the gel were brokenup by adding 0.1 part of oleic acid mono salt ofethylene diamine (prepared by mixing 1 mole. of oleic acid and 1 mole of ethylene diamine).

' Substantially the same results, i.e. complete break up of the gel, are obtained on replacing the above ethylene diamine monooleic acid salt with any of the following polyamino compounds of this invention:

Cresylic acid mono salt of ethylene'diamine (0.2 part) Naphthenic acid mono salt of ethylene diamine (0.2

part) i Naphthenic mono salt of :diethylene triamine (0.4

-part) Oleic acid mono salt of diethylene triamine (0.6 part of a 33% weight percent solution in xylene i.e. 0.2 part active ingredient) Oleic acid mono salt of 1,2-propylene diamine (0.6 part of a 50 weight percent solution in xylene containing 0.3 part activeingre dient) oleic acid mono salt of 2,3-butylene diamine (0.4 part) Example 4 c accelerated test, simulating field conditions, was devised todetermine the sensitivity of fuel oils to copper mercaptide gel formation and to evaluate the eifectiveness of various materials as inhibitors of gel formation. The test comprises passing or circulating (i.e. any number of passes) a sample of fuel oil over a specially prepared ,(corroded). ,copper. strip, at a specified temperature and rate of flow, and'then determining the increase in weight of the copper strip as a measure of the quantity of gel produced in c a given 'time- The corroded copper strips are specially prepared to ,speed up gel formation and to provide uniform conditions for the test. Preparation of corroded copper for the copper mercaptide gel testisas follows: I

,Copper strips, approximately 0.25 inch x 2.5 inches,

areroughly polished with,00 emery cloth, steel wool-polished until uniformly bright, then washed with light naphtha, and dried in air. The copper strips maybe stored in a tightly capped bottle forlO -IS days. f 150 ml. of henacne and 30 mlgof concentrated aqueous ammonium hydroxid are mixed and shakeri' vigorously for- 2 to 3 1 minutes to saturate the benzene with ammonia! -Ihe mix- "ture is allowed to' separate for to minutes and the aqueous layer is drawn off and' discarded. *Two or three polished copper strips, prepared as described above, are i immersed in the ammonia-saturated benzene for 24 hours. 1 The resulting corroded. copper strips are dried by allow- .ing the benzene to evaporate in air and then stored in a V tightly capped bottleuntil neededri. t H c When fuel oil whichis normally subjectto copper mer- -.;captide gel formation irizthe .jfield, i.e. contains naturally occurring active mercaptans, is allowed to flow over a corroded copper strip (prepared as above described) at a rate of one liter per 24 hours at 37 F., a characteristic yellowish gelatinous deposit is present on the copper strip after 24 hours. Fuel oils giving a negative test, i.e. no .gelappears and the copper strip shows no gain in weight, are considered free of active mercaptans, i.e. those forming insoluble copper mercaptide gel.

In order ot determine under controlled conditions the effectiveness of various materials in preventing insoluble gel, the active mercaptan content of fuel oil samples were standardized by incorporating in them known quantities of active mercaptans such as dodecyl mercaptan or 1:1 mixture of dodecyl mercaptan and xylyl mercaptan.

" In the following test, catalytically cracked fuel oil, containing (a) a total of 0.005 weight percent of active mercaptan sulfur (approximately004 g. S/liter), which was added to the fuel oil as 1:1 dodecyl and xylyl mercaptans, and (b) 0.0006 weight percent of diethylene triamine monooleate, was passed over a preweighed corroded copper strip (prepared as described above) at a rate of l liter/24 hours at 37 F. At the end of 24 hours, the cop per strip was washed with cyclohexane, air-dried and weighed. There was no increase in the weight of the copper strip. c j c 1 t In a control experiment under identical conditions and using the same base fuel containing the above mercaptans ;but withno added inhibitor present, the increase in weight the polyamines of this invention may be employed to intion.

"gel formation of at. least one polyamino' compound of the f group consisting of alkylene'primary diamines of 2 to 10 carbon atoms inwhich thejprimary amino groups are sep- 7 7 arated by 2; to 6 carbonatoms, dialkylene triamines of 4 arated by 2 to 4 carbon' atoms .and twoof the amino groups are primary amino groups, and mqno acid salts of said diamines'and'saidtriamines in which the acids are acids of 8 to about 22 carbon; atoms, l tnonohydric monoof the copper strip was 0.1462 g.

Following the above-described test procedure, any of hibit the formation of gelatinous deposit on copper; the

copper strip remains clean and shows essentially no inlimited to the specific embodiments disclosed therein.

While only certain polyamino compounds and compositions have beenemployed in the examples, mixtures of any two or more thereof may be similarly employed. Also,

other polyamino compounds and compositions, within the general disclosure, may be substituted therefor. Furthermore, the proportions, conditions, procedures, etc. may be varied widely as pointed out in the general description, without departing from the spirit and scope of thisinven- From the preceding disclosure, it isapparent that this invention providesnovel means and methods for inhibitcentrated solutions useful for preparing such fuel oil compositions and for breaking up preformed gels and clean ing equipment containing them. Thus, this invention solvesserious problems of the art and constitutes a valuable improvement in and contribution to the art.

The embodiments of the invention in which an exclusix e property or privilege is claimed are defined as follows: 1. A hydrocarbon distillate fuel oil which is in contact with a member of, the group consisting of copper, copper compounds and'brass, and which contains at least one mercaptan which normally tends to form a copper mercap tide gel, and a small proportion sufficieritto inhibit such to, 10 carbon atoms" in which the amino groups are sepselectedfrom the group consistingof monocarboxylicfatty nuclear phenols; and. mono'carbo'xylic petroleu'mhaph} thenic acids' of" about 8 to about 29'carbon atoms, s'aid polyamino compound being in a proportion equivalent toofrtoabout 5 parts of polyamino for each part of active mercaptan sulfur ill-the fuel oil. r g V 3 2. A hydrocarbon distillate fuel oil which is in contact with a member of the group' consisting'of copper, copper compounds and brass, and which contains at least one mercaptan which normally tends to form a copper mer- ,captide gel, and from about 0.5 to about 3 parts-byw weight for eaclipartvof active mercaptan sulfur present in the fuel oil'of at least one polyamino compound of the group consistingtofalkyleneprirnary diamines of 2 to 10' carbon altomsin whichthe primary amino groups are separated by 2'to 6 carbon atoms, dialkylene triamines of 4 to 10 carbon atomsinwhich the amino groups are separated by Zto 4'carbon'atoms and two of the amino groups are primary amino groups, and mono-acid salts of said diamines ltindsaid'triamines in which the acids are selected from the group"consisting of monoca'rboxylic fatty acids of 8,to about 22" carbon atoms, monohydric mononuclear phenols, and nionocar'boxylic petroleum naphthenic acids of about Stof about 29 carbon atoms.

3: A hydrocarbon distillate fuel on which is'in contact with a member of the group consisting of copper, copper compounds and brass, and which contains, at least one mercaptan whichrnormallytends to form a copper mercaptide gel, and a small proportion sufficient to inhibit 'sueh gel formation of attleasttone'alkylene primary dieminent 2 to? lolcarbonatoms in which the primary' amino groups'are'separatedfiby 2.to ,6 carbon atoms, said ,di-'

"stains being in aproportion of 0.1 'to about 5 parts thereof fiwf' ea'ch 'parttof active mercaptan sulfur in the fuel oil.

114. hydrocarbon distillate fuel oil which is in contact with a men'iberof the group consisting of copper, copper compounds and brass, and which contains at least one mercaptan which normally tends to form a copper mercipt-ide gel, "and a small" proportion suflici'ent' to iilhibit gel format ion-of at least one alkyleneprimary di- -amine:of-'2 to 6 carbon' atoms in which the primary amino groups are separated byz'to 3 carbon atoms,'saiddiamine "Being in a'proportion' of 1' toabout pa'rfts thereof for each part of active mercaptan: sulfur in the fuel oil a 5. A hydrocarbon distillate fuel oil which is in contact with a member of the group consisting of copper, copper compounds and brass, and which contains at least one mercaptan which normally tends to form a copper mercaptide gel, and a small proportion sufficient to inhibit such gel formation of at least one propylene primary diamine in which the primary amino groups are separated by 2 to 3 carbon atoms, said diamine being in a proportion of 0.1 to about 5 parts thereof for each part of activev mercaptan sulfur in the fuel oil. p 6. A hydrocarbon distillate fuel oil which is in contact with a member of the group consisting of copper, copper compounds and'bra'ss, and which contains at least one mercaptan which normally tends to form a copper mercaptide gel, and a small proportion sufficient to inhibit such gel formation of at least one dialkylene triamine of 4 to carbon atoms in which the amino groups are separated by 2 to 4 carbon atoms and two of the amino groups are primary amino groups, said triamine being in a proportion of 0.1 to about Sparts thereof for each part of active mercaptan sulfur in thefuel oil.

7. A hydrocarbon distillate fuel oil which is in contact with avme'mber of the group consisting of copper, copper V compounds and brass, and which contains at least one mercaptan which normally tends to form a copper rrlercaptide gel, and a small proportion sufficint to inhibit such gel formation of at least one dialkylene triamine of 4m 8 asserts carbon atoms in which the amino groups arefseparated r with-a member of the group consisting of copper; copper compounds and brass, and which contains at least one mercaptan which normally-tends to form a copper mercaptide gel, and a small proportion sufficient to inhibit such gel formation of diethylene triamine, said triamine being in a proportion of 0.1 to about 5 parts thereof for each part of active mercaptan sulfur in the fuel oil.

'v 9. A hydrocarbon distillate fuel oil which is in contact with a memberof the group consisting of copper, copper compounds and brass, and which contains at least one mercaptan which normally tends to form a'copper mercaptide gel, and a small proportion suflicient to inhibit such gel formation of at least one mono-acid salt of an alkylene primary diamine of 2 to 10 carbon atoms in which the prmiary amino groups are separated by 2 to 6 carbon atoms, the acid component of said salt being a monocarboxylic fatty acid of 8 to about 22 carbon atoms, said salt being in a proportion equivalent to 0.1 to about 5 parts of diamine for each part of active mercaptan sulfur in the fuel oil.

0. A hydrocarbon distillate fuel oil which is in contact with a member of the groupconsisting of copper,copper compounds and'brass, and which contains at least one mercaptan which normally tends to form a copper mercaptide gel, and a small proportion sutficient to inhibit such gel formation of at least one monooleate of an alkylene primary diamine of 2 to 6 carbon atoms in which the 7 primary amino groups are separated by 2 to 3 carbon atoms,,said monooleate being in a proportion equivalent to 0.1 to about 5 parts of diamine for each part of active mercaptan sulfur in the fuel oil.

11. A hydrocarbon distillate fuel oil which is in contact.

witharnember of the groupconsisting of copper, copper compounds and brass, and which contains at least one mercaptan which normally tends to form a copper mercaptide' gel, and a small proportion sufiicient to inhibit such gel formation of ethylene diamine monooleate, said 'monooleate being in a proportion equivalent to 0.1 to I active about 5 parts of ethylene diamine for each part' of mercaptan sulfur in the fuel oil. V

12'. A hydrocarbon distillate fuel oil which is in contact with a member. of the group consistingof copper, copper acid component of said salt being a monocarboxylic fatty acid of 8 to about 22 carbon atoms, said salt being in a proportion equivalent to 0.1 to about 5 parts of triamine for eachhpart of active mercaptan sulfur in the fuel oil.

13. A hydrocarbon distillate fuel oil which is in contact with amember of the group consisting of copper', copper compounds and brass, and which contains at least one mercaptan which normally tends to form a copper mercaptide gel, and a small proportion sufiicient to inhibit such gel formation of at least one monooleate of a dialkylene triamine of 4 to 8 carbon atoms .in which the amino groups are separated by2 to 3 carbon atoms and two of the amino groups are primary amino groups, said monooleate being in a proportion equivalentto 0.1 to about 5 parts of triamine for each'part of activemercaptan sulfur in the fuel oil.

14. A'hydrocarbon distillate fuel oil which is in contact with a member of the group consisting of copper, copper compounds and brass, and which contains at least one mercaptan which normally tends to form a copper mercaptide gel, and a small proportion suificient to inhibit such gel formation of diethylene triamine monooleate, said monooleate beingin a proportion equivalent to' 0.1 to

tive mercaptan sulfur in the fuel oil;

about 5 parts of diethylene triamine for each part of ac- I 15. A composition for liquefying' a gel, formed by the action of a copper mercaptide on a normally liquid hydrocarbon, .which composition consists essentially of a normallyliquid hydrocarbon having dissolved therein, in a concentration of from about 15% to about 70% by weight, .at least one polyamino compound ofithe group consisting of alkylene primary diamines of 2 to carbon atoms inwhich the primary ,amino groups are separated by 2 to 6 carbon atoms, dialkyl ene triamines of 4 to 10 carbon atoms in which the amino groups are separated by 2 to 4 carbon atoms and two of the amino groups are primary amino groups, and mono-acid salts of said diamines and said triamines in which the acids are selected from the group consisting of monocarboxylic fatty acids of 8 to about 22 carbon atoms, monohydric mononuclear phenols, and monocarboxylic petroleum naphthenic acids of about 8 to about 29 carbon atoms. I

16. A composition for liquefying a gel, formed by the action of a copp r mercaptide on a normally liquid hydro carbon, which composition consists essentially of a nor mally liquid hydrocarbon having dissolved therein, in a concentration of from about to about,50% by weight,

at least one mono-acid salt of analkylene primary diamine of 2 to 10 carbon atoms in which the primary amino groups are separated by 2 to-6 carbon atoms, the acid component of said salt being a monocarboxylic fatty acid of 8 to about 22 carbon atoms.

17. A compositionfor liquefying a gel, formed bythe action of a copper mercaptide on a normally liquid hydrocarbon, which'composition consists essentially of a normally liquid: hydrocarbon having dissolved therein, in a concentration of from about 15% to about 50% by weight, t

at least one mono-acid saltof a dialkylene triamine of 4 to 10 carbon atoms in whcih the amino'groups are separated by 2 to 4 carbon atoms and two of the amino groups are primary amino groups, the acid component of said salt being a monocarboxylic fatty acid of 8 to about 22 carbon atoms.

18. The process for liquefying agel, formed by the action of a copper mercaptide on a normally liquid hydrocarbon atomsin which the primary amino groups are sep arated by 2 to 6 carbon atoms, dialkylene triamines of 4 to 10 carbon atoms in which the amino groups, are sep arated by 2 to 4 carbon atoms and two of the amino groups are primary amino groups, and mono-acid salts of said diamines and said triamines in which the acids are selected from the group consisting of monocarboxylic fatty acids,

of .8 to a'bdut 22 carbon atoms, monohydric mononuclear phenols, and monocarboxylic petroleum naphthenic acids of about 8 to. about 29 carbon atoms. 1

a 19. The process for lique'fyinga gel,,formed by the action of a copper mercaptide ona normally liquid hydrocarbon, which comprises adding to said gel at least 1% by weight of at least one alkylene primary diamine of 2 to 4 carbon atoms in which the primary amino, groups are'separated by 2 to 3 carbon atoms. 1

20. .A hydrocarbon distillate fuel oilwhich is in, contact with a member of the group consisting of copper, copper compounds and brass, andwhich contains at least one mercaptan which normally tends to form a copper mercaptide gel, and a small proportion sufiicient to inhibit such gel formation of 1,2-propylene diamine monooleate, said monooleate being in aproportion equivalentto 0.1 to about 5 parts of-the diamine for each part of active mercaptan sulfur in the fuel oil. i i t i V References Cited in the file of this patent UNITED STATES PATENTS OTHER REFERENCES 1 Organic Nitrogen Compounds," Carbide and Carbon Chem.:Corp., recd March27, 1950, page 4. i

Industrial Solvents, by Mellan, Second Ed, 1950, Reinhold'Pub. Corp.. N.Y.,,page 424. i

How's Your Fuel-0il Quality? Osterhuut et al., Petraleum Processing, January 6, pages 67-71.

I (SEAL) UNITED STATES EATENTf OFFICE CERTIFICATE DF CORRECTION Patent No. 2,980.518 April 18, 1961 v I Philip L. Bartlett It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as "correctd below.

olumn 2, line 4L0 for lorough" read brought column 3, line 51, for "mixturese" read mixtures column 4 line 2, for "mOn acid" read mono-acid column 6 line 7 for 'Ytrimine" read triamine line 8, for "monoleates" read monooleates column 9, line 4, for "polyamino" read 'polyamine column 10, line 16, for "prmiary" read primary column 11 line 34, for "whcih" read which Signed and sealed this 10th day of October 1961 Attest:

ERNEST W. SWIDER DAVID L. LADD Attesting Officer I Commissioner of Patents USCOMM-DC UNITED STATE S PATENT f OFFICE CERTIFICATE OF CORRECTION Patent NO 2,980,518 April 18, 1961 Philip L. Bartlett It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent. should read as "corrected below.

Column 2, line 40, for hrouo h" read brought column 3, line 51, for "mixturese" read mixtures column 4, line 2, for "mon acid" read mono-acid column 6, line 7, for "trimine" read triamine line 8, for "monoleates" read monooleates column 9, line 4, for "polyamino" read polyamine column 10, line 16, for "prmiary" read primary column ll, line 34, for "whcih" read which Signed and sealed this 10th day of October 1961.

(SEAL) Attest:

ERNEST W. SWIDER 1 DAVID L. LADD I Commissioner of Patents Attesting Officer USCOM M-DC" 

1. A HYDROCARBON DISTILLATE FUEL OIL WHICH IS IN CONTACT WITH A MEMBER OF THE GROUP CONSISTING OF COPPER, COPPER COMPOUNDS AND BRASS, AND WHICH CONTAINS AT LEAST ONE MERCAPTAN WHICH NORMALLY TENDS TO FORM A COPPER MERCAPTIDE GEL, AND A SMALL PROPORTION SUFFICIENT TO INHIBIT SUCH GEL FORMATION OF AT LEAST ONE POLYAMINO COMPOUND OF THE GROUP CONSISTING OF ALKYLENE PRIMARY DIAMINES OF 2 TO 10 CARBON ATOMS IN WHICH THE PRIMARY AMINO GROUPS ARE SEPARATED BY 2 TO 6 CARBON ATOMS, DIALKYLENE TRIAMINES OF 4 TO 10 CARBON ATOMS IN WHICH THE AMINO GROUPS ARE SEPARATED BY 2 TO 4 CARBON ATOMS AND TWO OF THE AMINO GROUPS ARE PRIMARY AMINO GROUPS, AND MONO-ACID SALTS OF SAID DIAMINES AND SAID TRIAMINES IN WHICH THE ACIDS ARE SELECTED FROM THE GROUP CONSISTING OF MONOCARBOXYDRIC FATTY ACIDS OF 8 TO ABOUT 22 CARBON ATOMS, MONOHYDRIC MONONUCLEAR PHENOLS, AND MONOCARBOXYLIC PETROLEUM NAPHTHENIC ACIDS OF ABOUT 8 TO ABOUT 29 CARBON ATOMS, SAID POLYAMINO COMPOUND BEING IN A PROPORTION EQUIVALENT TO 0.1 TO ABOUT 5 PARTS OF POLYAMINO FOR EACH PART OF ACTIVE MERCAPTAN SULFUR IN THE FUEL OIL. 